The purpose of this study was to explore the role of mNGS in the diagnosis of PJI by detecting the presence of bacteria in periprosthetic tissues. Patients who were suspected of PJI and underwent surgery in our center were enrolled. Microbial culture and mNGS were performed on periprosthetic tissues collected intraoperatively. Patient age, body mass index (BMI), laboratory tests, microbial culture and mNGS results were recorded. The diagnostic performance of microbial culture and mNGS in the diagnosis of PJI was compared. A total of 44 patients were included. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of periprosthetic tissue microbial culture in the diagnosis of PJI were 72.72%, 77.27%, 76.19%, 73.91% and 75%, respectively. The sensitivity, specificity, PPV, NPV and accuracy of periprosthetic tissue mNGS in the diagnosis of PJI were 95.45%, 90.91%, 91.3%, 95.24% and 93.18%, respectively. The sensitivity and specificity of mNGS in the diagnosis of PJI were superior to those of microbial culture. Periprosthetic tissue can be used as an alternative to synovial fluid and sonication fluid, as mNGS can improve the diagnosis of PJI. mNGS of the periprosthetic tissues showed higher sensitivity than microbial culture.

Objectives: The purpose of this study was to explore the clinical value of metagenomic next-generation sequencing (mNGS) in the diagnosis of polymicrobial periprosthetic joint infection (PJI). Methods: Patients with complete data who underwent surgery at our hospital between July 2017 and January 2021 for suspected periprosthetic joint infection (PJI), according to the 2018 ICE diagnostic criteria, were enrolled, and all patients underwent microbial culture and mNGS detection, which were performed on the BGISEQ-500 platform. Microbial cultures were performed on two samples of synovial fluid, six samples of tissue, and two samples of prosthetic sonicate fluid for each patient. The mNGS was performed on 10 tissues, 64 synovial fluid samples, and 17 prosthetic sonicate fluid samples. The results of mNGS testing were based on the interpretation of mNGS results in the previous literature and the assertions of microbiologists and orthopedic surgeons. The diagnostic efficacy of mNGS in polymicrobial PJI was assessed by comparing the results of conventional microbial cultures and mNGS. Results: A total of 91 patients were finally enrolled in this study. The sensitivity, specificity, and accuracy of conventional culture for the diagnosis of PJI were 71.0%, 95.4%, and 76.9%, respectively. The sensitivity, specificity, and accuracy of mNGS for the diagnosis of PJI were 91.3%, 86.3%, and 90.1%, respectively. The sensitivity, specificity, and accuracy of conventional culture for the diagnosis of polymicrobial PJI were 57.1%, 100%, and 91.3%, respectively. mNGS had a sensitivity, specificity, and accuracy of 85.7%, 60.0%, and 65.2%, respectively, for the diagnosis of polymicrobial PJI. Conclusions: mNGS can improve the diagnosis efficiency of polymicrobial PJI, and the combination of culture and mNGS is a promising method to diagnose polymicrobial PJI.

Preoperative diagnosis is important for patients who need revision surgery due to PJI. Microbial culture plays an important role in PJI diagnosis, but the sensitivity of cultures is low when the sample amount is limited or when a patient is treated with antibiotics before sample collection. In this study, metagenomic next-generation sequencing (mNGS) was used to detect bacteria in preoperative puncture synovial fluid samples from patients with suspected PJI, and the preoperative and intraoperative culture results were compared to estimate the diagnostic efficiency. From July 2016 to December 2018, patients with suspected PJI who underwent prosthetic joint revision surgery were included, and the results of those who had been tested by preoperative synovial fluid culture and mNGS were obtained. The demographic characteristics, medical history, laboratory test results, culture results, and mNGS results of each patient were recorded. Then, the efficiency of preoperative synovial fluid mNGS was compared to that of synovial fluid culture for diagnosing PJI. A total of 37 patients were included, and 24 patients (25 joints) were diagnosed with PJI. The sensitivity, specificity and accuracy of preoperative synovial fluid mNGS were 92%, 91.7%, and 83.7%, respectively. The sensitivity, specificity and accuracy of preoperative synovial fluid culture were 52%, 91.7% and 43.7%, respectively. With a low volume of synovia (1 ml) mNGS can be performed with a higher sensitivity and specificity as compared to synovial culture. Thus, mNGS can be used as an effective supplemental method to improve diagnostic efficiency during the preoperative period.

Objective: To report on our clinical outcomes and on the experience of managing acute periprosthetic joint infection (PJI) with debridement, antibiotics, and implant retention (DAIR).Methods: We performed a retrospective review of all patients who were diagnosed with acute PJI after primary hip or knee replacement surgeries and who were managed with DAIR in our prospective joint replacement registry from 2008 to 2019. The diagnosis of PJI was made according to the 2011 Musculoskeletal Infection Society (MSIS) criteria. The symptom onset duration, inflammatory marker levels (i.e. C‐reactive protein [CRP], erythrocyte sedimentation rate [ESR], white cell count [WBC], and synovial WBC count), functional scores including the Knee Society Score (KSS), the KSS functional score and the Harris Hip Score (HHS), bacteriology, and surgical outcomes of the patients were tracked and recorded. A paired sample of joint fluid and tissues was also sent for a metagenomic next‐generation sequencing (mNGS) test. A paired‐samples t‐test was used to compare the differences in the inflammatory markers and functional scores before and after surgery.Results: A total of 24 patients with 7 infections after hip replacements and 17 infections after knee replacements were included. A total of 21 patients exhibited early postoperative infections, and 3 exhibited late acute hematogenous infections. During a mean follow‐up time of 29.2 ± 15.1 months, 22 patients were successfully treated, whereas 2 patients were unsuccessfully treated and required repeated DAIR. The overall success rate of DAIR was 91.7%. For staphylococcal infections, DAIR had a 100% success rate. Five patients who presented with symptoms between 4 and 8 weeks also achieved a 100% success rate. At the last follow‐up, the mean CRP level decreased from 52.6 ± 34.0 to 5.4 ± 3.5 (P < 0.001), and the mean ESR level decreased from 72.3 ± 34.3 to 20.2 ± 12.1 (P < 0.001). The mean KSS score increased from 44.8 ± 12.2 to 81.4 ± 9.2 (P < 0.001), and the mean KSS functional score increased from 38.1 ± 3.5 to 73.9 ± 23.0 (P < 0.001), and the mean HHS score increased from 34.4 ± 6.9 to 84.1 ± 15.1 (P < 0.001). The overall pathogen identification rate was 91.7% (22/24 cases). The success rates for Staphylococcus, Streptococcus, and the other pathogens were 100% (9/9 cases), 71.4% (5/7 cases), and 100% (6/6 cases), respectively.Conclusion: Debridement, antibiotics, and implant retention has a high success rate for the treatment of acute PJI and may be performed in selected patients whose symptoms have been sustained for over 4 weeks. A high rate of success for staphylococcal infections was reported with the use of DAIR.

The aim of this systematic review was to characterize the clinical features of adults with Salmonella osteomyelitis and summarize diagnosis and treatment methods to provide guidance for clinicians. This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines. We conducted a literature search in the PubMed, EMBASE, and Cochrane Library databases. Article screening and data extraction were performed by two reviewers individually. All the included studies were independently evaluated by two reviewers using the Methodological Index for Non‐Randomized Studies (MINORS) criteria. A total of 67 articles published between 1970 and 2019 were selected, which include 69 patients with an average age of 47.5 years (range, 18–79).The majority of cases (47.76%) occurred in immunocompetent adults without common risk factors. Aspiration and biopsy cultures were all positive in Salmonella osteomyelitis patients who underwent aspiration or biopsy. All infections were monomicrobial, and a total of 12 different serotypes were identified. The three most commonly reported Salmonella serotypes were Salmonella typhi (19 cases), Salmonella typhimurium (12 cases), and Salmonella enteritidis (11 cases). Only 12 of the 67 cases in our data (17.91%) had diarrhea symptoms, and 44 of the 67 cases (65.67%) had fever symptoms. Fifty‐nine of the 67 cases (88.06%) had local inflammatory manifestations, such as erythema, swelling, and tenderness in the affected area. The commonly reported involved sites were the vertebrae, femur, and tibia. Antibiotic therapy alone was utilized in 30 cases, and 24 patients (80.00%) were eventually cured. In total, 75.68% of patients achieved satisfactory results after treatment with surgery and antibiotics. Third‐generation cephalosporins were most commonly utilized, and antibiotic treatment was administered for an average of 11.3 weeks (95%CI, 8.31–14.37 weeks). Salmonella osteomyelitis should be considered in patients without any common risk factors. Aspiration or biopsy can facilitate the identification of pathogens to guide antibiotic choice. Empirical therapy with a third‐generation cephalosporin is recommended until the susceptibility of the strain is determined.

Objective: To evaluate the effectiveness of metagenomics next-generation sequencing (mNGS) for the detection of pathogenic microorganisms in periprosthetic joint infection (PJI) using the sonication fluid from removed prosthesis.Methods: In this prospective diagnostic cohort study, 44 patients who underwent revision arthroplasty in our hospital from December 2016 to December 2018 were screened. Seven cases were excluded due to incomplete clinical data, insufficient synovial fluid or failure of sequencing. According to the PJI diagnostic criteria recommended by the Musculoskeletal Infection Society (MSIS), the patients were defined as PJI or aseptic failure (AF). Conventional culture, sonication fluid culture and mNGS were performed, in order to assess the value of mNGS using sonication fluid for the diagnosis of PJI, and the mNGS results were analyzed and compared with the conventional and sonication fluid culture.Results: Among the 37 patients, 24 were diagnosed with PJI (64.86%), while 13 were diagnosed with aseptic failure. Among the 24 patients diagnosed with PJI, 15 cases (62.5%), 17 cases (70.8%) and 24 cases (100%) yielded positive results in conventional culture, sonication fluid culture and mNGS, respectively. In addition, mNGS detected the same pathogenic microorganisms in 16 out of the 17 (94.12%) culture-positive (conventional + sonication fluid) PJI cases. In the only one discrepancy case,Enterococcus faecaliswas identified in the cultures, whileEnterobacter cloacaewas detected by mNGS. In the AF group, the results of the conventional culture were all negative. Nevertheless,Staphylococcus epidermidiswas detected in the sonication fluid culture and mNGS in one case. The diagnostic sensitivity of mNGS for PJI was 100%, which was significantly higher than 70.83% (P = 0.039) of the sonication fluid culture and 62.5% (P = 0.021) of the conventional culture. The diagnostic specificity of mNGS for PJI was 92.31%, which was not significantly different (P > 0.05) from those of the conventional culture (100%) and sonication fluid culture (92.31%).Conclusion: We demonstrated that mNGS using sonication fluid can improve the detection rate of pathogenic microorganisms and provide valuable information for the diagnosis of PJI. In addition, mNGS can effectively identify pathogenic microorganisms in culture-negative PJIs cases, especially for the cases who have been treated with antibiotics before sample acquisition or have fastidious microorganisms. Therefore, this method can potentially help to guide the clinical use of antibiotics.